It's official. Doctor does not know best. And it comes not from the mouths of anti-medics but from the white coats of wisdom. Most family doctors believe newly pregnant women should be able to choose for themselves whether to have an abortion, without having to obtain medical approval: according to a survey released yesterday, 60% of GPs think abortion should be available on request in the first three months of pregnancy.

Over 30 years after abortion was legalised in Britain, it is still granted only at a doctor's discretion. A woman needs the signatures of two doctors prepared to say there is a risk of physical or mental injury to the mother or child if the pregnancy goes ahead. This has allowed some GPs to block access to a free abortion on the NHS because they object. And even if a GP agrees in principle, there are huge variations in funding.

The survey, by the family planning organisation Marie Stopes International, found that almost one GP in five said they were anti-abortion - that's 1,680 GPs nationwide. The Abortion Law Reform Association (ALRA) says 20% of women who want NHS abortions face stumbling blocks, while the Family Planning Association helpline receives 350 calls a month from women having difficulty getting information, consent or referral.

Rebecca was 26 and mother of a three-year-old when she became pregnant. She told her GP in Salford, Greater Manchester, that she wanted a termination because her family was complete. "He told me a baby is a gift from God and I'd love it once it was born. I felt trapped."

Her GP sent her away with anti-abortion literature to "really think about it. It was so patronising to suggest I didn't know my own mind," Rebecca says. "What did he want me to do? Plead insanity? Say I'd kill myself?" Instead she and her husband scraped together the £300 needed for a private abortion.

Some women, however, do not have alternatives. Those who cannot afford to go private may find themselves turned down by the NHS because of funding rationing by local health authorities. Eleanor became pregnant last year. She was 22, single and had decided she did not want children. Her GP told her that her health authority could not provide an abortion and that she should look in the back pages of magazines for the numbers of private clinics.

"I panicked," Eleanor says simply. "I couldn't afford to go private and I felt I'd rather kill myself than have the baby." Not knowing where to turn, she sought advice from a GP friend working for another health authority. This friend signed Eleanor on as a temporary patient and referred her immediately. The abortion was carried out in two weeks.

When a woman walks into her GP's surgery, she has no idea how her health authority judges eligibility for free treatment. In some areas, for example, a woman automatically qualifies for a free abortion if she is under 16; in others, she may qualify if she is under 21. And while one authority may consider "failed contraception" just cause, another may stipulate "severe mental health problems". As a result, huge regional differences now exist. For instance, in 1996, according to an ALRA report, Tees in the north-east provided 97% of all abortions on the NHS, while Redbridge and Waltham Forest in the south-east provided just 34%.

The fact that the majority of GPs think the law governing consent should be changed is significant, given that they are the gate-keepers to abortion provision. But while British abortion law is out of step with medical opinion, political opinion is proving harder to shift. Ann Furedi, director of the British Pregnancy Advisory Service, says MPs have exaggerated concerns about public opposition to abortion on request. "Politicians would much rather the service carried on as it is, shrouded in the sense that abortion is a moral wrong," she says. "The law is a fudge. It is humiliating for a woman to have to claim she can't cope with a child. Most women can but don't want to. When a woman goes to her GP with a wanted pregnancy, there is no suggestion that she pay for ante-natal care. If the same woman has an unwanted pregnancy, there is not the same responsibility to care for her."